Generation of steam



Aug. 13, 1929.

' v. z. CARACRISTI 1,724,560

GENERATION OF STEAM I Filed Feb. 25, 1926 3 Sheets-Sheet 1 56 i7 P Z EEEOOO O avwemtoz g- 13, 1929- v. z. CARACRISTI 1,724,560

GENERATI ON OF STEAM Filed Feb. 325, 1926 5 Sheets-Sheet 2 anven to:

$ GHovmc-af g- 1929. v. z. CARACRISTI 71,724,560

GENERATION OF STEAM Filed Feb. 25, 1926 3 Sheets-Sheet 5 Patented Aug. 13, 1929.

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Application filed February 25, 1926. Serial No. 90,444.

This invention relates to im rovements in the generation of steam un er stat onary boilers, and is especially useful where the fuel is to be burned in suspension, as, forexample, in the form of pulverized coal, carburetted oil or gas.

The nature and objects of my inventlon will be best understood from the following brief statement of stationary boiler practice.

In the designs of previous standard boilers, it has not been found practicable to obtain very high rates of firlng, such, for example, as are obtained in locomotivepractice. It is, therefore, one of the r1mary objects of my invention to increaset e rates of firing, and, therefore, the capacity of stationary boilers.

It is another object of the invention to obtain this result with what constitutes a relatively small amount of evaporatingI surface as compared to standard practice. t is still another'object of the invention to provide a simple arrangement whereby ordinary existing boilers may be readily converted into high capacity boilers.

My invention also contemplates the s1mplification of engineering work and manufacture by providing a novel arrangement of a boiler combustion chamber unit which can be used singly or in parts to construct boilers of varying size in accordance with the ultimate capacities desired.

How the foregoing, together with such other objects and advantages as. are herein! after pointed out, or may be incidentto my invention, are realized, is illustrated in preferred form in the accompanying drawings, wherein- Fig. 1 is a longitudinal vertical section through a boiler combustion chamber unit made in accordance with my invention.

Fig. 2 is a section taken'on' the line 2--2 of Fig. 1, and

Figs. 3 to 7, inclusive, are sectional views illustrating the application of my invention considered as a boiler combustion chamber unit to stationary boilers of various types, either existing or new. 7

Referring now to Figs. 1 and 2, it-will be seen that I have constructed a boiler combustion chamber unit indicated as a whole by the reference letter 'A, which unit is in the form of a fire box. The unit is constructed ,as follows: Headers 7 and 8 are arran of the shape mostclearly disclosed in Fig.

2, i. e., there are top and bottom sections 9 and 10, side sections 11 and 12, and an intermediate cross section 13. A rowoftubes 14 connect the lower portions of the side sections 11 and 12, and a row of tubes 15 connect the bottom sections of the headers. The tubes 14 and 15 constitute what may be termed a fire pan portion which may 'have a refractory lining 16.

A row of tubes 17 connect the up er ortions of the'side sections of the ea ers, these tubes being provided with longitudinally extending fins 18 whereby such tubes constitute, in effect, the vertical side walls of the combustion space above the fire pan. A row of vertically disposed finned tubes 19 close one end of the combustion space above the fire pan, and a row of bent finned tubes 20 close the opposite end of the combustion space above t e fire an. These tubes 20 carry a refractory wal portion or flash arch 2 The rear end of the fire pan is formed by a row of vertical finned tubes 22, and there are similar tubes 23 at the opposite end, which latter, however, are spaced apart to provide an opening 24 for the burner mechanism 25.

Finned tubes 26 extendfrom the rear section 13 of the rearheader upwardly andforwardly to the section 9 of the front header. These tubes 26 carry a refractory arch 26" which extends partway from the rear header to the front header.

. From the description thus far given, it will be seen that the fuel is introduced in the fire pan portion and is subjected to radiant heat from the refractory lining of the fire pan, and to radiant heat from the flash arch 21 and from the arch 26. and flame stream bends from a horizontal direction upwardly, and then turns underneath the arch toward the outlet or throat portion B provided by the main arch and the flash arch 21. On leavin the throat B the gaseous products of com ustion may be directed in any one of a number of different ways, as illustrated in Figs. 3 to 7, inclusive. 'A row of relatively widely s aced tubes 27 connect the upper sections 0 the headers 7 and 8, these tubes bein sufiiciently widely spaced apart to permit t e aseous products of combustion toflow re atively freely therebetween.

The fuel The total combustion the unit described is relatively-small, but

since the fuel and flame stream takes a somewhat sinuous course whereby adequate length of flame travel is provided, and smce the fuel is preferably admitted with a large portion of the air for combustion under conditions to produce violent and intense combustion, and since the fuel and flame stream is subjected to radiant heat from the refractories, thecombustion is completed within the combustion space afforded by the umt. The tubes 20, 22, 23, 26 and 27 are sub ected to radiant heat, and since the fuel 1s burned with a violent flame of intense temperature, heat is transmitted at a very high rate indeed, and thus a large capacity for a relatively small amount of'evaporating surface is obtained.

Additional air for combustion 1s admitted through inlets 28 arranged at opposite sides of the fire pan near the top thereof, such inlets being supplied with air from the air spaces 29 to either side of the fire pan. The air, in passing through the channels 29, becomes highly preheated, thus add1n g to the furnace temperature head, and asslstlng in obtaining more perfect and complete combustion within the combustion space. Such air also enters at right angles to the path of flame and serves to setup eddying tending to produce violent combustion and to improve bombustion.

It will be seen that the unit may be connected by tubes 30 to drums or to any other adjoining boiler art or structure in any one of the ways in icated in Figs. 3 to 7 1nclusive. As indicated in dot and dash lines in Fig. 2, the units may be placed side by side to vary the size of the installation as may be required. In Fig. 3 I have shown the unit applied to a horizontal boiler G of the cross drum type. In this case the bank of tubes of the cross drum boiler would be baflled to give a flow such as indicated by the arrows. When one or more units is associated with a boiler of this type, it will be seen that a very high capacit lnstallation of very small size results. When applying the unit to a boiler of the horizontal type it is preferable to incline the tubes of the unit in the same general fashion as the remaining boiler tubes.

In Fig. 4 I have shown aunit ap lied to a stationary boiler D of the fire tu s tyrip.

J In this case the products of combustion ta the path indicated by the arrows into the stack 31.

In'Fig. 5 another adaptation of a unit to a fire tube boiler is illustrated.

Fig. 6 illustrates the application of the invention to what may be termed a vertical boiler E. According to this arrangement the tubes 30 connect the upper portion of the header 7 with the upper or steam drum 32.

space presented bySuch tubes "30, in such case, would carry the sheathing 33.

In Fig. 7 I have shown a umt under what may be termed an inclined boiler. The header 8 in this case is supplied by means of downcomers 34 from the mud drum 35, and the tubes 30 constitute risers from the header 7 to the steam drum 36.

For circulatory reasons, the inclined arrangement of the tubes shown in Figs. 3 to 7 inclusive is preferred.

Referring now to certain details of the invention it willbe seen that the tubes 26 and 20 are relatively widely spaced apart so that T-shaped bricks may be employed for the arch and for the refractory portion carried on the tubes 20. By this arrangement but a relatively small portion of the bricks are exposed to the flame. Enough of the bricks, however, is exposed for purposes of ignition and combustion. The life of these bricks is extended because of the cooling effect of the tubes and of the fins which serve to carry heat to the tubes by conduction.

Further, with regard to the manner of introducing the fuel, this is preferably done by admitting a large portion of the air and coal together under high velocity, so that a violently eddying or violently agitated flame results. This method of introduction of the fuel and air tends to secure prompt admixture and violent combustion.

Refuse may be removed through the refuse hopper G.

Because of the shallowness of the unit, it may be installed beneath an existing boiler in the place of the stoker, whereby it is possible to very simply modify existing installations in order to increase capacity. The existing boiler in such case becomes largely an economizer section. V

I claim 1. A boiler unit including front and rear headers each having connected top, bottom- 2. A boiler unit including front and rear I headers each having connected top, bottom and side portions substantially "in the form a of a hollow rectangle, with cross connectin portions between the side portions of ca header intermediate the top and bottom portions thereof, tubes connecting the side and bottom portions of one header with the corresponding portions of the other header, and tubes connecting a cross connecting portion v and an are of. one header with the top portion of the other header, and tubes connecting said cross connecting portion with said top portion.

3. A boiler unit including front and rear headers each having connected top, bottom and side portions substantially in the form of a hollow rectangle, with cross connecting portions between the side portions of each header intermediate the top and bottom portions thereof, tubes connecting the side and bottom ortions of one header with the corresponding portions of the other header, and tubes connecting a cross connecting portion of one header with the top portion of the other header, together with an arch carried on said last tubes.

4. A boiler unit including front and rear headers each having connected top, bottom and side portions substantially in the form of a hollow rectangle with cross connecting portions between the side portions of each header intermediate the top and bottom portions thereof, tubes connecting the side and bottom portions of one header with corresponding portions of the other header, and tubes connecting a cross connecting portion of one header with the top portion of the other header, together with an arch carried on said last tubes, tubes connecting said cross connecting ortion with the said top portion,

carried on said tubes.

5. A stationary boiler unit of substantially greater length than height, having a header at each en thereof, tubes connecting said headers and arranged to form a box-like combustion chamber having av fire pan portion in the lower part thereof, a refractory lining for the fire panportion extending substantially from header to header, means for introducing fuel into one end of said fire pan to be burned in suspension in said chamber, the tubes of the boiler unit not associated with the fire pan being exposed to the radiant heat of the flame and other tubes substantiallydiagonally bisecting the portion of the combustion chamber above the fire pan.

6. A stationary boiler unit of substantial] greater len th than height, having a hea er at each end thereof, tubes connecting said headers and arranged to form a boxlike combustion chamber having a fire pan tially greater length than height, having a header at each end thereof, tubes connecting said headers and arranged to form a boxlike combustion chamber having a fire pan portion in the lower part thereof, a refractory lining for the fire pan portion extending substantially from header to header means for introducing fuel into one end 0 said fire pan to be burned in suspension in said chamber, the tubes of the boilerunit not associated with the fire pan being'exposed to the radiant heat of the flame and other tubes extending dia onally across a substantial part of the com ustion chamber, said latter tubes also being exposed to the radiant heat of the flame and carrying a refractory baflle.

8. A stationary boiler unit of substantial- 1y greater length than' height, having aheader at each end thereof, tubes connecting said headersand arranged to form a boxlike combustion chamber having a fire pan portion in the lower part thereof, a refractory lining for the fire pan portion extending substantially from header to header means for introducing fuel into one end 0 said fire pan to be burned in suspension in said chamber the tubes of the boiler unit not associated with the fire pan being exposed to the radiant heat of the flame and other tubes extending from the middle portion of one header to the upper portion of the other header and diagonally bisecting the combustion chamber.

In testimony whereof, I have hereunto signed my name. 

